# Copyright (c) 2018 Presto Labs Pte. Ltd.
# Author: leon

import logging
import json
from typing import List, Union

from tornado import gen

import coin.flow.topic_map as topic_map
from coin.base.param_util import to_list
from coin.exchange.base.ws.subscriber import WebsocketJsonSubscriberBase


def parse_channel(channel):
  market, symbol, event_type, arg = channel.split('.')
  return (symbol, event_type)


class FcoinSubscriber(WebsocketJsonSubscriberBase):
  def __init__(self,
               queue,
               group_id: str,
               worker_id: str,
               symbol: Union[List[str], str],
               close_callback=None,
               logger=None):
    super().__init__(close_callback, logger or logging.getLogger(__name__))
    self._symbol = to_list(symbol)

    self._register_url('wss://api.fcoin.com/v2/ws')
    self._publisher = None
    self._init_publisher(queue, group_id, worker_id)

  def _init_publisher(self, queue, group_id: str, worker_id: str):
    topic_depth = topic_map.search_topic_id('fcoin_ws_depth_%s%s' % (group_id, worker_id))[0]
    topic_trade = topic_map.search_topic_id('fcoin_ws_trade_%s%s' % (group_id, worker_id))[0]

    self._publisher = {
        'depth': queue.get_writer(topic_id=topic_depth[1]),
        'trade': queue.get_writer(topic_id=topic_trade[1])
    }

    self._enable_topic_event_publisher(queue,
                                       'fcoin_ws_topic_event', [topic_depth[0], topic_trade[0]])
    self._add_teardown_callback(self._teardown_publisher)

  @gen.coroutine
  def on_open(self):
    yield self._send_subscribe_request()

  @gen.coroutine
  def _send_subscribe_request(self):
    subscribe_depth_list = []
    subscribe_trade_list = []
    for symbol in self._symbol:
      self._logger.debug('Subscribing %s' % symbol)
      subscribe_depth_list.append('depth.L20.%s' % symbol)
      subscribe_trade_list.append('trade.%s' % symbol)

    subscribe_depth_str = json.dumps({'cmd': 'sub', 'args': subscribe_depth_list, 'id': '1'})
    yield self._ws.write_message(subscribe_depth_str)

    subscribe_trade_str = json.dumps({'cmd': 'sub', 'args': subscribe_trade_list, 'id': '1'})
    yield self._ws.write_message(subscribe_trade_str)
    yield gen.sleep(0.5)  # Sleep 0.5 second before next request

    self._publish_topic_event('START')
    self._logger.info('Subscribe done')

  def _teardown_publisher(self):
    if self._publisher:
      for _, publisher in self._publisher.items():
        publisher.close()
      self._publisher = None

  def on_message(self, timestamp: int, message: bytes):
    if self.stopped:
      return

    if 'type' not in message:
      self._logger.warning('Unknown message: %s' % message)
      return

    type = message['type']
    if type == 'topics':
      # Subscribe response.
      return

    event_type, *_ = type.split('.')
    try:
      self._publisher[event_type].write(timestamp, message)
    except (KeyError, ValueError):
      self._logger.error('Unknown channel: %s' % message)
